The present invention relates to an elevator apparatus and, more particularly, to guiding devices for a passenger cage used for preventing vibration.
A slight bend determined by the installation accuracy is produced on the guide rails for a passenger car of an elevator which are vertically provided in an elevator shaft.
Further, the building in which an elevator is installed gradually contracts under the weight of various equipments. If the building is multistoried, the amount of contraction increases, and the guide rails are further bent by the compression caused by the contraction of the building. If the bend of the guide rails increases, transversal vibration is caused during the upward and downward travel of the passenger cage. As the elevator travels at a higher speed, the transversal vibration the passengers feel becomes stronger, with the transversal vibration making the passengers not only uncomfortable but also uneasy.
Conventional guiding devices for guiding the passenger cage with rollers (wheels) contacting guide rails are proposed in Japanese Patent Laid-Open No. 74897/1987. In this proposal, an actuator is directly attached to the rollers (wheels), and the actuator is operated on the basis of the data on the bend on the guide rails which are measured and stored in advance by an acceleration detector, thereby reducing the transversal vibration of the passenger cage which is caused by the bend of the guide rails.
Another proposal is described in Japanese Patent Publication No. 39753/1983. In this proposal, the guiding devices which engage with the guide rails in a non-contacting state are provided, and apart from the guide rails, a vertical reference line is provided, whereby the guiding devices in the state of being non-contacting with the guide rails are so controlled that the distance between the reference line and the passenger cage is constant, thereby reducing the transversal vibration of the passenger cage.
Of the above-described prior art, in the proposal of Japanese Patent Laid-Open No. 74897/1987, it is assumed that the bend on the guide rails is constant irrespective of the unbalanced loading on the passenger cage due to the passengers and it no consideration is given to the fact that the bend on the guide rails actually changes in dependence upon the unbalanced loading condition. Thus, it is not always possible to reduce the transversal vibration of the passenger cage. In addition, change of the bend on the guide rails with time in the period from the time when the data on the bend in the guide rails is stored to the time when the data on the bend is rewritten by the remeasurement, the transversal vibration of the passenger cage is increased and deteriorated with time during this period. This proposal in which the guiding devices are directly driven by the actuator also involves a fear of the guiding devices decoupling from the guide rails when the actuator is out of order.
In the proposal of Japanese Patent Publication No. 39753/1983, it is necessary to provide the vertical reference line apart from the guide rails, so that the installation of the elevator is troublesome. In addition in this system, the guiding devices engage with the guide rails in a non-contacting state. However, when unbalanced load due to the passengers in the passenger cage or the impact load such as an earthquake is applied to the passenger cage, the non-contacting guiding devices solely cannot bear the load and require a back-up guiding device, which makes the elevator apparatus complicated.